While looking at TASK: Remove deprecated removed content wraps by Sebobo · Pull Request #3358 · neos/neos-development-collection · GitHub by @sebobo I remembered my recent change (see BUGFIX: Avoid use of removed isMethodSafe() by kdambekalns · Pull Request #3354 · neos/neos-development-collection · GitHub) and decided to post here.
According to Deprecating the old UI - #7 by sebastian we wanted to do this in 4.0.0:
disable the old UI completely by default
I am not sure if we actually did that, but my guess would be the old UI is no longer working anymore by now. If this is confirmed (or even if not), we might want to remove whatever leftovers we still have. I know that @markusguenther removed a lot of things related to the old UI… Probably most of the stuff is gone already, but some bits apparently still lurk in the shadows.
Any input on that, dear team?